Examination of the prediction of the planar piecewise continuous lumped muscle parameter model for walking gait with ankle-foot orthosis.

Goal: This work examines the use of a previously described piecewise continuous lumped muscle parameter (PPCLMP) model for predicting selected gait parameters for walking without and with ankle-foot orthoses (AFOs) of varying stiffnesses.

Methods: Two AFOs with low (3.4 Nm/deg) and high (6.

Field Observation of Hospital Food Service Workers and the Relationship between Customer Demand and Biomechanical Stress: A Case Study.

OCCUPATIONAL APPLICATIONSMotion analysis of three workers at a large hospital kitchen was conducted using video recordings as part of this case study. Workers were observed during both a high-demand period and a low-demand period to evaluate their exposure to physical risk factors for work-related musculoskeletal disorders. On average, workers' reaching posture did not change significantly with customer demand.

Selected movement and force pattern differences in rail- and rung-climbing of fire apparatus aerial ladders at 52.5° slope.

This study compares human climbing performance, including climbing speed and movement and force patterns, between rail- and rung-climbing styles for a moderate aerial ladder slope (52.5°). Hand and foot movements and forces were recorded for 9 male and 10 female firefighters as they ascended and descended a 3.

A planar piecewise continuous lumped muscle parameter model for prediction of walking gait.

Goal: This work aims to develop a planar piecewise continuous lumped muscle parameter (PPCLMP) model that can utilize inputs that can be obtained in a clinical or home setting using simple tools (e.g. video cameras and inertial sensors) to predict human walking gait.

Frequent template switching in postreplication gaps: suppression of deleterious consequences by the Escherichia coli Uup and RadD proteins.

When replication forks encounter template DNA lesions, the lesion is simply skipped in some cases. The resulting lesion-containing gap must be converted to duplex DNA to permit repair. Some gap filling occurs via template switching, a process that generates recombination-like branched DNA intermediates.

Role of RNase H enzymes in maintaining genome stability in Escherichia coli expressing a steric-gate mutant of pol V.

pol V (RumA'B) is a low-fidelity polymerase that promotes considerably higher levels of spontaneous "SOS-induced" mutagenesis than the related E. coli pol V (UmuD'C). The molecular basis for the enhanced mutagenesis was previously unknown.

Carpal tunnel syndrome and manual work: the OCTOPUS cohort, results of a ten-year longitudinal study.

Objective: The American Conference of Governmental Industrial Hygienists (ACGIH) proposed a method to assess the hand, wrist and forearm biomechanical overload based on exertions frequency (hand-activity level) and force use (normalized peak force). We applied the ACGIH threshold limit value (TLV)® method to a large occupational cohort to assess its ability to predict carpal tunnel syndrome (CTS) onset.

Methods: A cohort of industrial and service workers was followed-up between 2000 and 2011.

Effect of alternative video displays on postures, perceived effort, and performance during microsurgery skill tasks.

Physical work demands and posture constraint from operating microscopes may adversely affect microsurgeon health and performance. Alternative video displays were developed to reduce posture constraints. Their effects on postures, perceived efforts, and performance were compared with the microscope.

A frequency-duty cycle equation for the ACGIH hand activity level.

A new equation for predicting the hand activity level (HAL) used in the American Conference for Government Industrial Hygienists threshold limit value®(TLV®) was based on exertion frequency (F) and percentage duty cycle (D). The TLV® includes a table for estimating HAL from F and D originating from data in Latko et al. (Latko WA, Armstrong TJ, Foulke JA, Herrin GD, Rabourn RA, Ulin SS, Development and evaluation of an observational method for assessing repetition in hand tasks.

A hand speed-duty cycle equation for estimating the ACGIH hand activity level rating.

An equation was developed for estimating hand activity level (HAL) directly from tracked root mean square (RMS) hand speed (S) and duty cycle (D). Table lookup, equation or marker-less video tracking can estimate HAL from motion/exertion frequency (F) and D. Since automatically estimating F is sometimes complex, HAL may be more readily assessed using S.

Identification of technique variations among microvascular surgeons and cases using hierarchical task analysis.

Unlabelled: A hierarchical taxonomy was developed for identifying differences among microvascular surgeons and cases and for investigating the impact of those differences on case outcome. Hierarchical task analysis was performed on eight microvascular anastomosis cases. The analysis was simplified by redefining subtasks and elements to only describe actions and adding attributes to describe the work object, method, tool, material, conditions and ergonomics factors.

Maximum hand-rung coupling forces in children: the effects of handhold diameter.

Objective: To quantify the effect of handhold size (diameter) on the maximum breakaway strength between a hand and handhold for children.

Background: Falls from playground equipment are a major cause of childhood injury and death. It is unclear if recommendations for handholds on playground equipment are too broad.

Feasibility and safety of a novel in vivo model to assess playground falls in children.

Background: Falls are the leading cause of nonfatal unintentional injuries among hospitalized children with playground equipment accounting for more than 50%. National standards for playground rung and rail design exist, but there a lack of in vivo models available to test these standards. We developed a novel in vivo model to test rung and rail design.

The objective assessment of experts' and novices' suturing skills using an image analysis program.

Purpose: To objectively assess suturing performance using an image analysis program and to provide validity evidence for this assessment method by comparing experts' and novices' performance.

Method: In 2009, the authors used an image analysis program to extract objective variables from digital images of suturing end products obtained during a previous study involving third-year medical students (novices) and surgical faculty and residents (experts). Variables included number of stitches, stitch length, total bite size, travel, stitch orientation, total bite-size-to-travel ratio, and symmetry across the incision ratio.

The effect of handhold orientation, size, and wearing gloves on hand-handhold breakaway strength.

Objective: The aim of this study was to quantify the effect of handhold orientation, size (diameter), and wearing a glove on the maximum breakaway strength between a hand and handhold.

Background: Manual breakaway strength is known to be greatly reduced for vertical compared with horizontal handholds, but oblique orientations have yet to be studied.

Method: For this study, 12 young adults (6 female) attempted to hold on to fixed overhead cylindrical handholds with one hand in low-speed simulated falls as forces on the handhold were recorded in two experimental designs.

Validation of the ACGIH TLV for hand activity level in the OCTOPUS cohort: a two-year longitudinal study of carpal tunnel syndrome.

Objectives: This study aimed to evaluate the risk of musculoskeletal disorders to the hand-wrist system. The American Conference of Governmental Industrial Hygienists (ACGIH) proposed threshold limit values (TLV©) based on hand activity level (HAL) and normalized peak force (PF). We validated ACGIH TLV© in OCTOPUS, a large cohort study on carpal tunnel syndrome (CTS).

The effect of visualization method on the performance of simulated microsurgery tasks.

The operating microscopes may be a significant cause of fatigue and discomfort in surgeons. The need for the microscope to be placed over the operating field forces surgeons to remain at the microscope's eyepieces at an uncomfortable posture for the entirety of the surgery. This study compared the effects on microsurgical task performance for four visualization methods: a monocular microscope, a binocular microscope, a three-dimensional (3D) flat-panel television display and a two-dimensional (2D) flat-panel television display.

Quantification of hand grasp force using a pressure mapping system.

The goal of this study was to use a pressure sensor to measure the force distribution and contact area of the hand when gripping, pushing, and pulling a cylinder. Data was collected from 10 subjects with no hand impairments and from 1 subject with rheumatoid arthritis (RA). Subjects grasped an aluminum cylinder wrapped with a Tekscan pressure sensor and performed each trial at 25%, 50%, and 100% maximum voluntary exertion.

The effects of functional limitations on soldier common tasks.

This paper describes the findings associated with the ability of an individual to perform the United States Army's Common Soldier Tasks of: "Maintaining an M16-Series Rifle" , "Protect Yourself from Chemical, Biological, Radiological, and Nuclear (CBRN) Injury or Contamination with Mission-Oriented Protective Posture (MOPP) Gear", and "Protect Yourself from Chemical and Biological (CB) Contamination Using Your Assigned Protective Mask." The analysis was conducted using data compiled from videos of a Soldier performing the given tasks at Walter Reed Army Medical Center. The findings reflect the opinions of researchers in identifying potential elements, which impose abnormal, irregular, and/or extraneous effort when performing the tasks as outlined in STP-21-1-SMCT - Soldier's Manual of Common Tasks: Skill Level I.

The effect of viewing angle on wrist posture estimation from photographic images using novice raters.

Observational assessment of wrist posture using photographic methods is theoretically affected by camera view angle. A study was conducted to investigate whether wrist flexion/extension and radial/ulnar deviation postures were estimated differently by raters depending on the viewing angle and compared to predictions using a quantitative 2D model of parallax. Novice raters (n=26) estimated joint angles from images of wrist postures photographed from ten different viewing angles.

Hand-handhold coupling: effect of handle shape, orientation, and friction on breakaway strength.

Objective: The aim was to determine the maximum force that can be exerted on an object before it is pulled or slips from the grasp of the hand ("breakaway strength") for fixed overhead handholds of varying orientation, shape, and friction.

Background: Many studies have quantified hand strength by having participants squeeze, pull on, or create torque on an object or handle, but few studies have measured breakaway strength directly.

Method: In two experiments, hand strength was measured as both overhead breakaway strength for handholds typical of fixed industrial ladders and as maximum isometric grip strength measured using a common Jamar grip dynamometer.

Effects of handle orientation, gloves, handle friction and elbow posture on maximum horizontal pull and push forces.

Biomechanical models were evaluated for effects of handle orientation, handle material, gloves and arm posture on maximal pull/push force. Eight healthy subjects performed maximum pull/push exertions on handles with two different orientations and two different surface materials, using bare hand and two types of glove as well as two arm postures. The empirical data supported the proposed biomechanical models: Pull/push forces for the bare hand on a rubber handle decreased 10% when the handle was parallel to the pull/push direction, compared with when perpendicular to it.

Biomechanical analysis for handle stability during maximum push and pull exertions.

This study investigated the effect of handle stability on maximum push/pull force. It was hypothesised that people apply force in directions deviated from the pure push/pull direction to generate a moment that assists producing greater push/pull force when the handle position is fixed (stable) compared to when it is not fixed (unstable). Eight healthy subjects performed maximum push and pull exertions on a stable and an unstable handle in a seated posture, while maximum push/pull force, vertical force and lateral force were recorded.

The effects of insertion method and force on hand clearance envelopes for rubber hose insertion tasks.

Objective: The aim of this study was to determine how hand space for manual insertion of flexible hoses is affected by insertion method and force.

Background: Adequate space is needed during assembly tasks in which workers join parts together with their hands. Hose installations are an example of such a task.